Every few years, my wife asks me "What do you need to learn for the next five years of your career?"
I think that question is enough. I don't know enough to plan ten years out; technology moves kind of fast. But five years out I can often see the rough shape of what's coming.
The trick is remembering to ask the question every few years...
It's good to have a direction of travel, but don't overdo it: You want to make God laugh? Tell him your plans.